Ultrasonic Testing
Main features
*Surface and sub-surface detection.
*This detection method uses high frequency sound waves, typically above 2MHz to pass through a material.
*A probe is used which contains a plezo electric crystal to transmit and receive ultrasonic pulses and display the signals on a cathode ray tube or digital display.
*The actual display relates to the time taken for the ultrasonic pulses to travel the distance to the interface and back.
*An interface could be the back of a plate material or a defect.
*for ultrasound to enter a material a couplant must be introduced between the probe and specimen.
主要特点
*具备表面与近表面检测能力
*该检测技术采用超过2MHz的高频声波穿透材料
*使用内置压电晶体的探头收发超声波脉冲，并通过阴极射线管或数字显示屏呈现信号
*实际显示数据对应超声波传播至界面并返回所需时间
*界面可为板材背面或内部缺陷
*为实现超声波导入待检材料，需在探头与试件间施加耦合剂
英文原表：
ProbesFrequencyCrystalApplication
0°4 to 5 MHzTwin 10mmLamination scanning, weld scanning if cap ground flush
45°4 to 5 MHzSingle 10mmWeld body scanning root pass and plate thickness above 15mm
60°4 to 5 MHzSingle 10mmWeld body scanning plate thickness above 10mm
70°4 to 5 MHzSingle 10mmWeld body scanning all plate thickness
中文翻译表：
探头角度频率晶片规格应用范围
0°4-5 MHz双晶 10mm分层扫描，适用于焊冠经打磨处理的焊缝扫描
45°4-5 MHz单晶 10mm焊缝主体扫描：适用于根部焊道检测及板厚超过15mm的工况
60°4-5 MHz单晶 10mm焊缝主体扫描：适用于板厚超过10mm的工况
70°4-5 MHz单晶 10mm焊缝主体扫描：适用于全板厚工况
Advantages
Rapid results.
Both surface and
Sub-surface detection.
Safe.
Capable of measuring the depth of defects.
May be battery powered.
Portable.
Disadvantages
Trained and skilled operator required.
Requires high operator skill.
Good surface finish required.
Defect identification.
Couplant may contaminate.
No permanent record.
Calibration Required.
Ferritic material (mostly).
中文翻译：
优点
检测结果快速
兼具表面与近表面缺陷检测能力
安全性高
能够测量缺陷深度
可电池供电
便于携带
缺点
需培训且要求操作人员技能娴熟
对操作人员技能要求高
需要良好表面光洁度
缺陷识别存在难度
耦合剂可能造成污染
无法提供永久记录
需进行校准
(主要适用于)铁素体材料
Magnetic Testing
Main features
Surface and slight sub-surface detection.
Relies on magnetization of component being tested.
Only Ferro-magnetic materials can be tested.
A magnetic field is introduced into a specimen being tested.
Methods of applying a magnetic field: yoke, permanent magnet, prods and flexible cables.
Fine particles of iron powder are applied to the test area.
Any defect which interrupts the magnetic field will create a leakage field, which attracts the particles.
Any defect will show up as either a dark indication or, in the case of fluorescent particles under UV-A light, a green/yellow indication.
地道中文翻译：
主要特点
可检测表面及近表面缺陷
基于被检测部件的磁化特性
仅适用于铁磁性材料
向被测试样引入磁场
磁化方法包括：磁轭法、永久磁铁法、触头法及缠绕电缆法
在检测区域施加细微铁磁性粉末
任何破坏磁场的缺陷都会形成漏磁场，从而吸附磁粉
缺陷显示特征：普通磁粉呈深色痕迹，荧光磁粉在紫外灯下呈黄绿色痕迹
Magnetic Particle Testing
Typical sequence of operations to inspect a weld
Apply areas to be tested.
Apply contrast paint.
Apply magnetisation to the component.
Apply ferro-magnetic ink to the component during magnetising.
Interpret the test area.
Post clean and de-magnatise if required.
Magnetic Particle Testing
Advantages
Simple to use.
Inexpensive.
Rapid results.
Little surface preparation required.
Possible to inspect through thin coatings.
Disadvantages
Surface or slight sub-surface deposition.
Magnetic materials only.
No indication of defects depths.
Only suitable for linear defects.
Detection is required in two directions.
Penetrant Testing
Main features
Detection of surface breaking defects only.
This test method uses the forces of capillary action.
Applicable on any material type, as long they are non porous.
Penetrants are available in many different types:
Water washable contrast.
Solvent removable contrast.
Water washable fluorescent.
Solvent removable fluorescent.
Post-emulsifiable fluorescents.
Magnetic ink composition
Non-fluorescent ink between 1.25% to 3.5% by volume.
Fluorescent ink between 0.1% to 0.3% by volume.
Light requirements
White light 500 lux minimum.
Black light 20 lux on a ghost lifting 2.
Pure light 40 lux on a ghost lifting capacity
AC current 4.5 kg pole spacing 300mm or less.
DC current 18 kg pole spacing above 75mm.
PC sampling of spacing i.e. 200mm spacing = 1200 emps.
磁粉检测
典型焊缝检测操作顺序
确定待检测区域。
施加反差增强剂。
对部件进行磁化。
在磁化过程中向部件施加铁磁性磁悬液。
判读检测区域。
必要时进行后续清理和退磁。
磁粉检测
优点
操作简单。
成本低廉。
结果快速。
表面准备要求低。
可透过薄涂层进行检测。
缺点
仅能检测表面或近表面缺陷。
仅适用于磁性材料。
无法显示缺陷深度。
仅适用于线性缺陷。
需沿两个方向进行检测。
渗透检测
主要特点
仅检测表面开口缺陷。
此检测方法利用毛细作用力。
适用于任何非多孔材料。
渗透剂有多种不同类型：
水洗型着色。
溶剂去除型着色。
水洗型荧光。
溶剂去除型荧光。
后乳化型荧光。
磁悬液成分
非荧光磁悬液，体积浓度 1.25% 至 3.5%。
荧光磁悬液，体积浓度 0.1% 至 0.3%。
光照要求
白光至少 500 勒克斯。
黑光下磁痕显示 2 处需 20 勒克斯。
纯光下磁痕显示能力需 40 勒克斯。
交流电，极间距 300mm 及以下，提升力 4.5 kg。
直流电，极间距 75mm 以上，提升力 18 kg